rwnd_press tracks the pressure on the recieve window.  Every
timer the receive buffer overlows, we truncate the receive
window and then grow it back.  However, if we don't track
the cumulative presser, it's possible to reach a situation
when receive buffer is empty, but rwnd stays truncated.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

SCTP fast recovery algorithm really applies per association
and impacts all transports.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

Right now, sctp transports are not fully initialized and when
adding any new fields, they have to be explicitely initialized.
This is prone to mistakes.  So we switch to calling kzalloc()
which makes things much simpler.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

We don't need to force the T3 timer any more and it's
actually wrong to do as it causes too long of a delay.
The timer will be started if one is not running, but if
one is running, we leave it alone.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

The 'resent' bit is used to make sure that we don't update
rto estimate based on retransmitted chunks.  However, we already
have the 'rto_pending' bit that we test when need to update rto,
so 'resent' bit is just extra.  Additionally, we currently have
a bug in that we always set a 'resent' bit and thus rto estimate
is only updated by Heartbeats.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

commit 4951feda0c60d1ef681f1a270afdd617924ab041
    sctp: Do no select unconfirmed transports for retransmissions

added code to make sure that we do not select unconfirmed paths
for data transmission.  This caused a problem when there are only
2 paths, 1 unconfirmed and 1 unreachable.  In that case, the next
retransmit path returned is NULL and that causes a kernel crash.

The solution is to only change retransmit paths if we found one to use.
Reported-by: NFrank Schuster <frank.schuster01@web.de>
Signed-off-b: Vlad Yasevich <vladislav.yasevich@hp.com>

This assignment isn't needed because we did it earlier already.

Also another reason to delete the assignment is because it triggers a
Smatch warning about checking for NULL pointers after a dereference.
Reported-by: NVlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

This patch implement sctp association probing module, the module
will be called sctp_probe.

This module allows for capturing the changes to SCTP association
state in response to incoming packets. It is used for debugging
SCTP congestion control algorithms.

Usage:
  $ modprobe sctp_probe [full=n] [port=n] [bufsize=n]
  $ cat /proc/net/sctpprobe

  The output format is:
    TIME     ASSOC     LPORT RPORT MTU    RWND  UNACK <REMOTE-ADDR   STATE  CWND   SSTHRESH  INFLIGHT  PARTIAL_BYTES_ACKED MTU> ...

  The output will be like this:
    9.226086 c4064c48  9000  8000  1500    53352     1 *192.168.0.19  1     4380    54784     1252        0     1500
    9.287195 c4064c48  9000  8000  1500    45144     5 *192.168.0.19  1     5880    54784     6500        0     1500
    9.289130 c4064c48  9000  8000  1500    42724     5 *192.168.0.19  1     7380    54784     6500        0     1500
    9.620332 c4064c48  9000  8000  1500    48284     4 *192.168.0.19  1     8880    54784     5200        0     1500
    ......
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

sctp_chunk_is_data macro is defined to decide that
whether a chunk is data chunk or not.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

An unconfirmed transport is one that we have not been
able to reach since the beginning.  There is no point in
trying to retrasnmit data on those transports.  Also, the
specification forbids it due to security issues.
Reported-by: NFrank Schuster <frank.schuster01@web.de>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

While doing retranmit, if control chunk exists, such as
FORWARD TSN chunk, and the DATA chunk can not be bundled with
this control chunk because of PMTU limit, no DATA chunk
will be retranmitted in the current implementation. This
patch makes sure to retranmit at least one DATA chunk in this case.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

While lookup the output route, we do not set the src and dest
port. This will cause we got a wrong route if we had set the
outbund transport to IPsec with src or dst port.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

PR-SCTP extension section 3.5 Sender Side Implementation of PR-SCTP:
  C5) If a FORWARD TSN is sent, the sender MUST assure that at
      least one T3-rtx timer is running.

So this patch fix to assure at least one T3-rtx timer is running
if a FORWARD TSN is or will to sent.
Signed-off-by: NWei Yongjun <yjwei@cn.fujitsu.com>
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

SHUTDOWN-ACK is alaways sent to the primary path at the first time,
but should better transmit SHUTDOWN-ACK chunk to the same destination
transport address from which it received the SHUTDOWN chunk.
Based on the work from Wei Yongjun <yjwei@cn.fujitsu.com>.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

The function should use the address family of the address when
trying to determine the length of the structure.
Signed-off-by: NVlad Yasevich <vladislav.yasevich@hp.com>

We dereference "sk" unconditionally elsewhere in the function.  

This was left over from:  b30bd282 "ip6_xmit: remove unnecessary NULL
ptr check".  According to that commit message, "the sk argument to 
ip6_xmit is never NULL nowadays since the skb->priority assigment 
expects a valid socket."
Signed-off-by: NDan Carpenter <error27@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

potential uninitialized variable num_xfrms

fix compiler warning: 'num_xfrms' may be used uninitialized in this function.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
----
 net/xfrm/xfrm_policy.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sock_recv_ts_and_drops() is fat and slow (~ 4% of cpu time on some
profiles)

We can test all socket flags at once to make fast path fast again.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When queueing a skb to socket, we can immediately release its dst if
target socket do not use IP_CMSG_PKTINFO.

tcp_data_queue() can drop dst too.

This to benefit from a hot cache line and avoid the receiver, possibly
on another cpu, to dirty this cache line himself.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Since commit 95766fff ([UDP]: Add memory accounting.), 
each received packet needs one extra sock_lock()/sock_release() pair.

This added latency because of possible backlog handling. Then later,
ticket spinlocks added yet another latency source in case of DDOS.

This patch introduces lock_sock_bh() and unlock_sock_bh()
synchronization primitives, avoiding one atomic operation and backlog
processing.

skb_free_datagram_locked() uses them instead of full blown
lock_sock()/release_sock(). skb is orphaned inside locked section for
proper socket memory reclaim, and finally freed outside of it.

UDP receive path now take the socket spinlock only once.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes:
o Bugfix: Flow control was causing the device to be destroyed.
o Bugfix: Handle CAIF channel connect failures.
o If the underlying link layer is gone the net-device is no longer removed,
  but closed.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes:
 This is a complete re-write of the socket layer. Making the socket
 implementation more aligned with the other socket layers and using more
 of the support functions available in sock.c. Lots of code is copied
 from af_unix (and some from af_irda).
 Non-blocking mode should be working as well.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes:
o Function cfcnfg_disconn_adapt_layer is changed to do asynchronous
  disconnect, not waiting for any response from the modem. Due to this
  the function cfcnfg_linkdestroy_rsp does nothing anymore.
o Because disconnect may take down a connection before a connect response
  is received the function cfcnfg_linkup_rsp is checking if the client is
  still waiting for the response, if not a disconnect request is sent to
  the modem.
o cfctrl is no longer keeping track of pending disconnect requests.
o Added function cfctrl_cancel_req, which is used for deleting a pending
  connect request if disconnect is done before connect response is received.
o Removed unused function cfctrl_insert_req2
o Added better handling of connect reject from modem.
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes:
o Added functions cfsrvl_get and cfsrvl_put.
o Added support release_client to use by socket and net device.
o Increase reference counting for in-flight packets from cfmuxl
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Changes:
 o Renamed cfcnfg_del_adapt_layer to cfcnfg_disconn_adapt_layer
 o Fixed typo cfcfg to cfcnfg
 o Renamed linkid to channel_id
 o Updated documentation in caif_dev.h
 o Minor formatting changes
Signed-off-by: NSjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Move some declarations around to make it clearer which variables
are being used inside loop.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The recently introduced bridge mulitcast port group list was only
partially using RCU correctly. It was missing rcu_dereference()
and missing the necessary barrier on deletion.

The code should have used one of the standard list methods (list or hlist)
instead of open coding a RCU based link list.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix unsafe usage of RCU. Would never work on Alpha SMP because
of lack of rcu_dereference()
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

By coding slightly differently, there are only two cases
to deal with: add at head and add after previous entry.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This reverts commit ff65e827.

As explained by Stephen Hemminger, the traversal doesn't require
RCU handling as we hold a lock.

The list addition et al. calls, on the other hand, do.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Noticed by Michał Mirosław.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now there's no need to use this fuction directly because it's handled by
register_pernet_device. So to make this simple and easy to understand,
make this static to do not tempt potentional users.
Signed-off-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Current socket backlog limit is not enough to really stop DDOS attacks,
because user thread spend many time to process a full backlog each
round, and user might crazy spin on socket lock.

We should add backlog size and receive_queue size (aka rmem_alloc) to
pace writers, and let user run without being slow down too much.

Introduce a sk_rcvqueues_full() helper, to avoid taking socket lock in
stress situations.

Under huge stress from a multiqueue/RPS enabled NIC, a single flow udp
receiver can now process ~200.000 pps (instead of ~100 pps before the
patch) on a 8 core machine.
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

batch skb dequeueing from softnet input_pkt_queue to reduce potential lock
contention when RPS is enabled.

Note: in the worst case, the number of packets in a softnet_data may
be double of netdev_max_backlog.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Idea from Eric Dumazet.

As for placement inside of struct sock, I tried to choose a place
that otherwise has a 32-bit hole on 64-bit systems.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>

reimplement softnet_data.output_queue as a FIFO queue to keep the
fairness among the qdiscs rescheduled.
Signed-off-by: NChangli Gao <xiaosuo@gmail.com>
Acked-by: NEric Dumazet <eric.dumazet@gmail.com>
----
 include/linux/netdevice.h |    1 +
 net/core/dev.c            |   22 ++++++++++++----------
 2 files changed, 13 insertions(+), 10 deletions(-)
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

RFC 1122 says the following:
...
  Keep-alive packets MUST only be sent when no data or
  acknowledgement packets have been received for the
  connection within an interval.
...

The acknowledgement packet is reseting the keepalive
timer but the data packet isn't. This patch fixes it by
checking the timestamp of the last received data packet
too when the keepalive timer expires.
Signed-off-by: NFlavio Leitner <fleitner@redhat.com>
Signed-off-by: NEric Dumazet <eric.dumazet@gmail.com>
Acked-by: NIlpo Järvinen <ilpo.jarvinen@helsinki.fi>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

I prefer that the hlist be only accessed through the hlist macro
objects. Explicit twiddling of links (especially with RCU) exposes
the code to future bugs.

Compile tested only.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Use existing inline function.
Signed-off-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>